At sea to Cape Verde
The National Geographic Endeavour has kept pace with technological advances and today the ship bristles with antennae. Their roles vary, from Global Positioning System to tell us where we are to our satellite telephone and internet connections so that this report can reach you. One antenna is our link to the Automatic Identification System (AIS) by which each ship can broadcast it's identity via a Very High Frequency (VHF) signal. VHF signals typically operate on a range that is more-or-less line of sight, so we normally know which ships are within about 20 nautical miles of our position. So far on this trip the AIS had been more or less empty of contacts in the remote expanses of the South Atlantic.
We have left the south-east trade winds behind us, passed through the doldrums and the Intertropical Convergence Zone. Today we entered the north-east trade winds and are about 350 nautical miles off the coast of West Africa. These winds have brought with them dust from the Sahara desert, resulting in a hazy appearance to the horizon and a thin film of dust covering the superstructure of the ship by the end of the day. In addition to the haze, the dust has given us some unusual radio effects.
The Saharan dust in the atmosphere has created excellent conditions for the propagation of VHF signals. Throughout the day our AIS has been showing signals from ships up to an amazing 750 nautical miles away and the radio has been filled with chatter from these ships (one of which was also called Endeavour). The AIS signals are linked to our sophisticated electronic chart programme, the screen of which has been crowded with a multitude of contacts today, in contrast with the isolation of our journey to date.
The National Geographic Endeavour has kept pace with technological advances and today the ship bristles with antennae. Their roles vary, from Global Positioning System to tell us where we are to our satellite telephone and internet connections so that this report can reach you. One antenna is our link to the Automatic Identification System (AIS) by which each ship can broadcast it's identity via a Very High Frequency (VHF) signal. VHF signals typically operate on a range that is more-or-less line of sight, so we normally know which ships are within about 20 nautical miles of our position. So far on this trip the AIS had been more or less empty of contacts in the remote expanses of the South Atlantic.
We have left the south-east trade winds behind us, passed through the doldrums and the Intertropical Convergence Zone. Today we entered the north-east trade winds and are about 350 nautical miles off the coast of West Africa. These winds have brought with them dust from the Sahara desert, resulting in a hazy appearance to the horizon and a thin film of dust covering the superstructure of the ship by the end of the day. In addition to the haze, the dust has given us some unusual radio effects.
The Saharan dust in the atmosphere has created excellent conditions for the propagation of VHF signals. Throughout the day our AIS has been showing signals from ships up to an amazing 750 nautical miles away and the radio has been filled with chatter from these ships (one of which was also called Endeavour). The AIS signals are linked to our sophisticated electronic chart programme, the screen of which has been crowded with a multitude of contacts today, in contrast with the isolation of our journey to date.
